This invention relates to an apparatus for and method of measuring the physical strength of a person. More particularly, it is directed to an apparatus for and method of dynamically measuring the instantaneous power of a nonrepetitive muscular force as, for example, the force of a leg extending motion, based on a power theory. Specifically, the apparatus and method involve measuring the instantaneous power of a dynamic, nonrepetitive multi-articular motion as, for example, a vertical jump.
Conventional physical strength tests, such as vertical jump tests, reciprocal jump tests, and dorsal muscle tests, have had the following problems:
(1) It is often difficult to synthesize separate test results sized for evaluation, since various functions are evaluated separately.
(2) Evaluation standards are ambiguous. For example, the evaluation standard of a vertical jump is the height to which one can jump; however, this is merely an indirect index of physical strength.
(3) There is no standardized scientific support.
(4) Unusual movements may be involved, the loads involved are large, and injuries are liable to occur.
Presently, there is growing interest in physical conditioning. Thus, a method of and apparatus for easily, safely and accurately measuring physical strength is needed. In response, a study on unified indices of physical strength based on a power theory is underway.
According to the power theory, physical strength is measured as the capacity of energy (an integrated value of the power) or as an index. Methods for the generation of power can be classified according to energy developing mechanisms within a living body. For each method of power generation, an upper limit of power is measured and used as an index of physical strength for the corresponding energy generating mechanism.
Specifically, the mechanisms are classified as follows:
(a) Oxygen-present energy mechanism PA0 (b) Lactic acid-type anaerobic energy mechanism PA0 (c) Non-lactic acid-type anaerobic energy mechanism
Duration: Infinite PA1 Evaluation of upper limit power: Power available at 75% of the maximum heart rate, etc. PA1 Main factor for energy generation: Oxygen PA1 Duration: About 30 seconds PA1 Evaluation of upper limit power: Average power, critical power, etc. PA1 Main factor for energy generation: Glycogen PA1 Duration: About 7 seconds PA1 Evaluation of upper limit power: The optimum value determined by speed and developing force of the peak power around 5 to 6 seconds. PA1 Main factor for energy generation: ATP-CP type chemical energy.
With respect to energy mechanisms (a) and (c), a measuring apparatus using a bicycle ergometer has been practiced by the applicant (Japanese Patent Examined Publication No. 42694/1989). "AEROBIKE" and "POWERMAX" are also known apparatuses developed from the above art. (Both "AEROBIKE" and "POWERMAX" are registered and pending trademarks of Combi Corporation; the former is Japanese Trademark Registration No. 1840771, and the latter is Japanese Trademark Publication No. 61-42348.) As for energy mechanism (b), the Wingate test is an example.
Power measurement by means of a bicycle ergometer has the advantage of rhythmic and efficient pedaling motion which lessens the chance of injury.
The instantaneous power of a dynamic, nonrepetitive muscular force in continuous muscular exercise of one's legs or other similar multi-articular exercise can be advantageous in every day life as, for example, when one must hastily avoid an obstacle. One apparatus for measuring the instantaneous power of a nonrepetitive muscular motion of legs is disclosed in Japanese Utility Model Unexamined Publication No. 18103/1988. In this publication, the leg extending power is transmitted to an hydraulic or pneumatic cylinder, and the physical strength of a subject is measured according to data from the cylinder.
In the above leg extending, power measuring apparatus, the adjustment of the cylinder and the like is very difficult, and the variation of the load in accordance with the speed makes it difficult to accurately measure instantaneous power. Further, with a hydraulic cylinder, the response time of the hydraulic pressure is so slow as to make measurement accuracy unreliable.
Instantaneous power generated by a leg extending force is conventionally calculated from the amount of work done on a brake load. The foot plate, having to receive the force generated when the user or subject kicks it with his full power within a very short time (about 0.3 seconds), is heavy and rigid in structure. Kinetic and inertial energy, as absorbed by the foot plate and the rotating system of a brake, are not taken into consideration in such calculations. Therefore, it is difficult to accurately measure the instantaneous power generated by leg extension.